Pump unit arranged in an inner tank of a fuel tank of a motor vehicle

ABSTRACT

The invention relates to a pump unit arranged in an inner tank ( 3 ) of a fuel tank, comprising a fuel pump ( 5 ) which is used to pump fuel to the internal combustion engine of a motor vehicle; an ejector pump ( 21 ) which is connected to the fuel pump ( 5 ) and used to pump fuel out of the fuel tank into the inner tank ( 3 ); and at least one filter element ( 20:31 ) which is used to filter fuel, wherein a housing part which is connected to the fuel pump ( 5 ) is provided with at least one channel ( 30;33;35;47 ) for guiding said fuel. In order to simplify the structure of the pump unit ( 2 ) and to enable substantial pre-assembly, the housing part ( 24;40 ) is configured in such a way that it can hold the at least one filter element ( 20;31 ), and the channel ( 30;33;35;47 ) is exclusively guided inside the housing part ( 24; 40 ) from the ejector pump ( 21 ) and/or the fuel pump ( 5 ) to the filter element ( 20;31 ).

BACKGROUND OF THE INVENTION

[0001] The invention relates to a pump unit which is to be arranged in asurge chamber of a fuel tank of a motor vehicle, having a fuel pumpwhich is provided for pumping fuel to an internal combustion engine ofthe motor vehicle, having an ejector pump which is connected to the fuelpump and is used to pump fuel out of the fuel tank into the surgechamber, and having at least one filter element for filtering fuel, ahousing part which is connected to the fuel pump having at least onechannel which is provided for guiding the fuel.

[0002] Pump units of this type are frequently used in motor vehiclestoday and are known from practice. The housing part of the known pumpunit has a flange with which it is inserted into a recess of the surgechamber and is sealed with respect to the latter. The channel leading tothe intake side of the ejector pump is guided as far as the flange. Thefilter element is fastened on the lower side of the surge chamber andhas an edge with which it is sealed with respect to the surge chamber.

[0003] A disadvantage of the known pump unit is that it is of verycomplex construction and pre-assembly to form individual subassemblieswhich can be combined with one another is not possible.

[0004] The invention is based on the problem of designing a pump unit ofthe type mentioned at the beginning in such a manner that it is ofparticularly simple construction and enables substantial pre-assembly.

BRIEF DESCRIPTION OF THE INVENTION

[0005] This problem is solved according to the invention in that thehousing part is designed to hold the at least one filter element, andthe channel is guided from the ejector pump and/or from the fuel pump tothe filter element exclusively within the housing part.

[0006] This design enables the pump unit according to the invention tobe pre-assembled with the filter element and the housing part outsidethe fuel tank and the surge chamber and then to be fitted in the surgechamber as a pre-assembled unit. Since the channel leading to the filterelement is arranged exclusively within the housing part, multiple sealsbetween the housing part and the filter element are avoided. The pumpunit according to the invention thereby requires a particularly smallnumber of components. The pump unit according to the invention istherefore of particularly simple construction and can be manufacturedparticularly cost-effectively.

[0007] A contribution is made to further reducing the number ofcomponents of the pump unit according to the invention if the ejectorpump is manufactured as a single part with the housing part.

[0008] The ejector pump could be connected to the fuel pump via a hoseline, for example. A contribution is made to further cutting down theassembly of the pump unit according to the invention if the housing parthas a channel for a working-fluid line of the ejector pump.

[0009] Separate manufacturing of the ejector pump and housing part isgenerally required if the pump unit is provided for different surgechambers and fuel tanks. The pre-assembly of the pump unit according tothe invention becomes particularly simple during the separatemanufacturing of the housing part if the housing part contains theejector pump or has a holder for the ejector pump or of a subregion ofthe ejector pump.

[0010] According to another advantageous development of the invention,the connection of the housing part to the fuel pump is highly stable ifthe housing part has an annular flange which is prestressed against thefuel pump. Furthermore, the housing part thereby requires a particularlysmall amount of material to be used.

[0011] The housing part could, for example, be rolled together with ahousing part, which is manufactured from sheet metal, of the fuel pump.However, according to another advantageous development of the invention,the assembly and the removal of the housing part become particularlysimple if the housing part has a plug-in connection on the fuel pump.

[0012] [lacuna] inlet and outlet regions arranged very close to oneanother. However, in order to avoid flow losses, the inlet regionsgenerally have to be very large. The pump unit according to theinvention has very low flow losses and turns out to be particularlycompact if the channel of the working-fluid line of the ejector pump hasa pipe length which is guided to the fuel pump through a connectingbranch which has the inlet region.

[0013] In particular if housing parts are manufactured from plastic, thepump unit according to the invention requires particularly fewcomponents to be fitted if the filter element is manufactured integrallywith the housing part. This design enables the filter element to bedesigned, for example, in the form of a perforation on a wall of thehousing part.

[0014] The invention permits numerous embodiments. To further clarifyits basic principle, two of these are illustrated in the drawing andwill be described below. In the drawing

[0015]FIG. 1 shows a lower subregion of a pump unit according to theinvention together with adjacent components of a fuel tank, in a partialsection,

[0016]FIG. 2 shows a sectional illustration through the pump unit fromFIG. 1 along the line II-II,

[0017]FIG. 3 shows a housing part of the pump unit according to theinvention from FIG. 1 in an enlarged sectional illustration along theline III-III,

[0018]FIG. 4 shows a lower subregion of a further variant of the pumpunit according to the invention, in a partial section.

DETAILED DESCRIPTION OF THE INVENTION

[0019]FIG. 1 shows a bottom region of a fuel tank 1 of a motor vehiclewith a pump unit 2 inserted therein. The pump unit 2 comprises a surgechamber 3 with a fuel pump 5 which is driven by an electric motor 4. Thefuel pump 5 has an impeller 8 which is arranged between two fixedhousing parts 6, 7 and can be driven by the electric motor 4. Two ringsof vane chambers 9-11 are arranged in the impeller 8. In the region ofthe vane chambers 9-11, the housing parts 6, 7 have partially annularchannels 15-17 which extend in each case from an inlet region 12 to anoutlet region 13, 14. The partially annular channels 15-17 form with thevane chambers 9-11 pump chambers 18, 19 for pumping the fuel. Sinceradially outer vane chambers 9, 10 which lie opposite each other mergeinto one another, the flow passes axially through the impeller 8 in thisregion. The fuel pump 5 is therefore designed as a side-channel pump.During rotation of the impeller 8, fuel is sucked out of the surgechamber 3 via a filter element 20. The fuel is guided through theradially outer pump chamber 18 by the pump unit 2 to an internalcombustion engine (not illustrated) of the motor vehicle. The radiallyinner pump chamber 19 is used to pump fuel as working fluid to anejector pump 21. The ejector pump 21 sucks up fuel via an opening in thebottom of the surge chamber 3 and pumps it into the surge chamber 3.

[0020] The ejector pump 21 and connecting components 22, 23 leading tothe filter element 20 and the fuel pump 5 are manufactured as a commonhousing part 24. Furthermore, the common housing part 24 has a pipelength 26 with a channel 27 which is guided from the radially inner pumpchamber 19 to a nozzle 25 of the ejector pump 21. The housing part 24also has a channel 30 which is guided as far as an inlet region 29 ofthe ejector pump 21, which region is arranged between the nozzle 25 anda mixing pipe 28. The channel 30 is guided through the bottom of thesurge chamber 2. A filter element 31 is arranged at that end of thechannel 30 which faces the fuel tank 1. This filter element 31 ismanufactured integrally with the housing part 24. The connectingcomponent 22 of the housing part 24 is sealed with respect to the lowerhousing part 7 of the fuel pump 5 by means of an O-ring 32, and can beplugged into said housing part. Furthermore, the housing part 24 has achannel 33 which is guided from the filter element 20, which is arrangedin the surge chamber 3, as far as the inlet region 12 of the pumpchambers 18, 19. A collecting space 34 for fuel which is to be sucked upis situated above the intlet region 29 of the ejector pump 21.

[0021]FIG. 2 shows that the connecting component 22 has a partition 35to separate off the channel 33 of the inlet region 12 of the pumpchambers from the collecting space 34. The pipe length 26 which isguided to the nozzle 25 (illustrated in FIG. 1) of the ejector pump 21is guided through the collecting space 34. This design makes it possiblefor the radially inner, partially annular channel 17 to extend over aparticularly large angular region. The radially outer, partially annularchannel 16 ends shortly before the inlet region 12 of the fuel pump 5.

[0022]FIG. 3 shows the housing part 24, which has the channels 27, 30,33, from FIG. 1 in a sectional illustration along the line III-III. Itcan be seen here that the filter element 20 which is arranged within thesurge chamber 3 has a connecting stub 36 which is plugged into thechannel 33 of the housing part 24 and a filter cloth 37 which isfastened to the connecting stub 36. The housing part 24 can therefore bepre-assembled together with the filter element 20 to form aconstructional unit and can then be connected to the fuel pump 5 fromFIG. 1. The filter element 31 protruding into the fuel tank has a filtercloth 38 manufactured as a single piece with the housing part 24, andtherefore forms a constructional unit with the housing part 24.

[0023]FIG. 4 shows a pump unit 39, in which a housing part 40 which isfastened to the fuel pump 5 has a flange 41. This flange 41 is grippedfrom behind by a crimped sheet-metal edge 42 of the fuel pump 5.Furthermore, the housing part 40 has a holder 43 to plug an integrallymanufactured ejector pump 44 into. As an alternative to the integralmanufacturing of the ejector pump, the housing part 40 may also have aholder (not illustrated) for a subregion of the ejector pump. Thehousing part 40 has a channel 45 for connecting the inlet region 12 ofthe fuel pump 5 to the filter element 20, which is arranged within thesurge chamber, a channel 46 for connecting the ejector pump 44 to theoutlet region 14 of the radially inner pump chamber 19, and a channel 47for connecting the inlet region 29 of the ejector pump to the filterelement 31, which is arranged in the fuel tank 1. The housing part 40has a collecting space 34 for fuel which is to be sucked up by theejector pump 44 and a pipe length 49 for accommodating the channel 46.Otherwise, the housing part 40 can be designed in the same manner as thehousing part 24 of the pump unit 2 from FIG. 1.

1. A pump unit (3, 39) which is to be arranged in a surge chamber (2) ofa fuel tank (1) of a motor vehicle, having a fuel pump (5) which isprovided for pumping fuel to an internal combustion engine of the motorvehicle, having an ejector pump (21, 44) which is connected to the fuelpump (5) and is used to pump fuel out of the fuel tank (1) into thesurge chamber (2), and having at least one filter element (20, 31) forfiltering fuel, a housing part (24, 40) which is connected to the fuelpump (5) having at least two channels (30, 33, 45, 47) which areprovided for guiding the fuel, characterized in that the housing part(24, 40) is designed to hold the at least one filter element (20, 31),and the channels (30, 33, 45, 47) are guided from the ejector pump (21,44) and from the fuel pump (5) to the filter element (20, 31)exclusively within the housing part (24, 40).
 2. The pump unit asclaimed in claim 1, characterized in that the ejector pump (21) ismanufactured as a single part with the housing part (24).
 3. The pumpunit as claimed in claim 1 or 2, characterized in that the housing part(24, 40) has a channel (27, 46) for a working-fluid line of the ejectorpump (21, 44).
 4. The pump unit as claimed in defined 1, characterizedin that the housing part (40) has a holder (43) for the ejector pump(44).
 5. The pump unit as defined in claim 4 wherein the housing part(40) has an annular flange (41) which is prestressed against the fuelpump (5).
 6. The pump unit as defined in claim 1 wherein the housingpart (24) has a plug-in connection on the fuel pump (5).
 7. The pumpunit as defined in claim 1 wherein the filter element (31) ismanufactured integrally with the housing part (24, 40).
 8. The pump unitas defined in claim 1 wherein the housing part (24, 40) has a collectingspace (34) between an inlet region (29) of the ejector pump (21, 44) andthe fuel pump (5).
 9. A pump unit (3, 39) which is to be arranged in asurge chamber (2) of a fuel tank (1) of a motor vehicle, having a fuelpump (5) which is provided for pumping fuel to an internal combustionengine of the motor vehicle, having an ejector pump (21, 44) which isconnected to the fuel pump (5) and is used to pump fuel out of the fueltank (1) into the surge chamber (2), and having at least one filterelement (20, 31) for filtering fuel, a housing part (24, 40) which isconnected to the fuel pump (5) having an inlet region (12) and at leastone channel (30, 33, 45, 47) which is provided for guiding the fuel, andbeing designed to hold the at least one filter element (20, 31); and thechannel (30, 33, 45, 47) being guided from the ejector pump (21, 44)and/or from the fuel pump (5) to the filter element (20, 31) exclusivelywithin the housing part (24, 40), characterized in that a channel (27,46) of the working-fluid line of the ejector pump (21, 44) has a pipelength (26, 49) which is guided to the fuel pump (5) through aconnecting branch which has the inlet region (12).
 10. The pump unit asclaimed in claim 9, characterized in that the pipe length (26, 49) ismanufactured integrally with the housing part (24, 40).